Method of and means for constructing composite liquid tanks



y 1934- F. w. CHAPPELL 1,964,870

METHOD OF AND MEANS FOR CONSTRUCTING COMPOSITE LIQU ID TANKS Filed Jan.,8, 1934 2 Sheets-Sheet 1 ll IL II II II I] II I II II I I II II I II H II 11 liuf I] I II gwuewtoz July 3, 1934. F. w. CHAPPELL METHOD OF AND MEANS FOR CONSTRUCTING COMPOSITE LIQUID TANKS Filed Jan. 8, 1934 2 Sheets-Sheet 2 Patented July 3, 1934 UN ITE'DI STATES,

PATENT METHOD OFAND MEANS FOR CONSTRUCT' INGCOMPOSITE LIQUID TANKS' Application'January 8, 1934, Serial No. 705,762

Claims.

This invention relates-to new and-useful im-- provements in methods of and means for constructing composite liquid tanks.

The usual practice in constructing composite 5 liquid tanks is tobuild a reinforcing frame of steel, iron or other metal. A complete form is then built entirely around this frame and the concrete, or other similar material, pouredtherein. After the concrete sets, the form is removed id and a reinforced concrete tankis had. When the tank is filled with liquid, the steel frame, or reinforcing within the concrete is placed under a strain and a certain'amount of stretch or radial expansion of the frame displaces or disrupts the concrete, causing large cracks to appear therein, which are not only unsightly and detractfrom the appearance of the tank, but

also cause leaks in said tank-w The expansion or stretch of the steel frame is unavoidable for it is inherent in metal when the same is placed under a strain.

One object ofthe invention is to provide an improved composite tank which is positively liquid tight.

Another object of the invention is to provide an improved methodof constructing. areinforced concrete tank which consists of constructing a preliminary concrete wall around a reinforcing metal frame, filling this partially completed tank with liquid, wherebythe pressure-of said liquid will place the metal frame under a strain and cause radial expansion thereof, and then completing the concrete tank with the frame in its expanded position, thereby obviating the possiin the completed'tank.

A further object of the invention is to provide an improved methodvof constructing reinforced concrete tanks, wherein a reinforcing frame is in combination with a'cement gun, or other similar apparatus, the form being arranged to be moved circumferentially around the reinforcing frame as each section of the wall is completed, whereby the labor" and expenditure'coincident' with constructing a complete form entirely around the reinforcing frame for pouring the concretetherein is saved.

Still another object of theinvention is to provide an improved reinforcedconcrete tank having an expansion joint between the wall and floor of said tank, whereby heat and'cold expansionand retraction, alternate wetting and dry-..

ing, and other varying conditions are taken-care providing an expansion joint-between the wall bility of the frame stretching or expanding withfirst'built and a movable sector form is employed s metal or woven welded wire.-

of to prevent cracking the concrete connection between said wall and floor.

An important object of the invention is to provide an improved method of constructing a reinforced composite tank, which consists first, erecting a reinforcing metal framework on a suitable foundation; next, constructing a suitable floor for the tank; then erectinga preliminary concrete wall around the reinforcing frame and and the-floor, then introducingliquid; into 'this I partially completed tank, whereby the reinforcing metal frame therein is placed undera strain and undergoes a radial expansion, which displaces the concrete of the wall and causes cracks therein, then covering the entire outside of the preliminary wall with a layer of concrete to close the cracks while the frame is in its expanded position, and then finally completing the tank by adding an inner layer of concrete to the wall after the outer layer has set, whereby any leaks in the tank are closed and the reinforcing frame is firmly and permanently held within thewall in a stretched or expanded-position;

Figure -1 is a partial vertical sectional view of the reinforcing frame erected on the foundation and floor of a tank and constructed in accordance with theinvention,

Figure 2 is a horizontal cross sectional View taken on the line 22 of Figure 1,

the next step in the construction of the tank;-

Figure 4 is a detail of the expansion joint be 'tween the wall andfloor of thetank,

Figure 5 is a transverse vertical of the partially completed tank, therein,

Figure 6 is a horizontal cross-sectional view,- taken on the line 6-6 of Figure5,

Figures 7 and 8 are horizontal cross-sectional '95 views, showing the final steps .of the construction of the tanks,'and

- Figure 9 is an enlarged partial vertical sectional view showing the completed tank;

In the drawings thenumeral 10 designates a sectional View showing liquid 7 suitable annular foundation which is preferably made of concrete, or other similar material, *Thisfoundation may be supported onpiles, or other" supports, (not shown) ,or it maybe setdirectlyin the ground. A circularmetal cage or reinforcing frame 11 is erected and supported in an annular trench 10' in the foundation-10. The reinforcingframe may be of steelbars, or steel fabric, either'expanded :I have shown-the frame constructed of a plurality of flat vertical bars 12 connected together by circular tie bars 13. It is pointed out that the frame may be of any desired construction, so long as it serves the purpose of reinforcing the completed tank. A circular fioor 14, suitably reinforced and made of the same material as the foundation 10, is constructed within said foundation in concentric relation thereto. The diameter of the fioor is smaller than the inner diameter of the foundation, whereby an annular space 16 is provided therebetween. The space 16 is filled with tar, asphalt, or other material having a certain elasticity, and thus an expansion joint is formed between the foundation and floor. It is pointed out that the floor may be of any desired depth.

For constructing the wall of the tank, a movable arcuate sector form 20 is provided. The form extends vertically the height of the reinforcing frame 11 and is supported adjacent the outer side thereof in the trench 10 in the foundation 10. By observing Figure 3, it will be seen that the sector form merely extends around a portion of the frame 11 and is detachably secured to said,

frame by clamps 20, or other suitable means.

After the arcuate sector form 20 has been placed and clamped in position, concrete 'or other similar material is shot against said form from the inside of the frame 11. For this purpose a cement gun, or other similar apparatus (not shown), which can be purchased on the open market, can be used. The concrete thus applied will completely surround that portion of the reinforcing frame 11 (Figure 3), whereby said frame is embedded therein. After this portion of the wall is formed, the arcuate sector form 20 is moved around and another section of the wall is constructed in the same manner. This operation is continued until an entire circular wall 21 is completed. The wall 21 is made a predetermined thickness which is sufficient to hold the liquid placed in the tank. It is pointed out that the wall is connected to the foundation within the annular trench 10 therein. The thickness of the wall 21 is an important feature of the method, for this wall is made only strong enough to holdliquid and need not be liquid-tight.

To complete the expansion joint to make the connection between the wall 21 and floor 14, a

circular flashing ring 18, preferably made of copper or other non-corrosive metal, is positioned over the asphalt 1'7 in the space 16 between the floor and foundation. The ring is provided with an annular rib 18' at its central portion and the ring is held in position by perforated metal keepers 19, which are riveted or suitably secured to the ends of the ring. The keepers may be annular rings or they may be short perforated bars. The keepers rest on the foundation 10 and fioor 14 and concrete is shot onto said keepers from the inside of the tank. This gunned concrete passes through the perforations in the keepers and firmly adheres to the concrete of the foundation and fioor. An annular space 22 is provided in the floor above the rib 18' in the ring 18 and this space is filled with asphalt 22, similar to the filling in the space 16, whereby the expansion joint is completed.

7 Although it may be possible to eliminate the perforations in the keepers 19, it has been found that there is no possibility of liquid leaking through the joint when the perforations are pro vided, for a concrete to concrete bond is formed through said perforations. Since asphalthas a certain elasticity and can move without cracking,

it is obvious that the only actual immovable connection between the floor and the wall 21 is the flashing ring 18. Due to the rib 18 this ring will compensate any radial movement of the walls without affecting the concrem bond between the floor and said walls.

After the expansion joint has been completed, liquid is introduced into the tank (Figure 5) and the liquid pressure against the wall 21 will place the reinforcing frame 11 under a strain. Since every metal inherently has a certain amount of stretch, the liquid pressure will cause the frame 11 to stretch or undergo a radial expansion. This expansion of the frame will displace and disrupt the concrete wall 21 outwardly, causing cracks 24 (Figure 6) to appear therein. This outward displacement of the wall will tend to break the connection of the wall with the floor, but the expansion joint will take care of this movement.

With the liquid still within the wall 21 and the reinforcing frame 11 in its expanded position, a

layer 25 of concrete is shot (Figure 7) onto the outer surface of the wall 21, with a cement gun or similar apparatus (not shown) The air pressure behind the nozzle will drive the water back through the cracks 24 and seal the cracks permanently. By observing Figure 9, it will be seen that the layer 25 serves to fill that portion of the trench 10' which the wall 21 has not covered, whereby a more secure bond between the wall and foundation is had. The layer 25 must be of sufficient thickness so that upon setting, or drying, it will be sufficient to hold the frame 11 in a stretched or expanded position and thereby preventing it returning to its normal or unstressed position.

After the outside layer 25 has been completed and set, the liquid is removed from the tank and an inside layer 26 of concrete is shot on the inner surface of the wall 21. This inner layer not only serves to close the cracks 24 more completely, but also, after setting, aids the outer layer 25 in holding the frame 11 in a stretched position. Thus, the frame can at no time return to its normal position.

It would, of course, be possible to do away with the expansion joint between the wall and floor and to fill up cracks formed therein by the displacement of concrete due to expansion of the reinforcing frame 11 by adding a top layer of concrete. However, the expansion joint will also allow for heat and cold expansion and contraction of the reinforcing frame 11, alternate wetting and drying, and other causes, without cracking the concrete. p

The wall of the tank, as formed, will be permanently liquid-tight because the steel frame 11 embedded therein is held fixed in its stretched or expanded position. Subsequent fillings with liquid will have no effect on the wall. Further, by using this method of constructing the tank, it is possible to use higher stresses in the steel used in constructing the frame, and thereby reduce the quantity of steel, as well as the cost of the tank. Of course the limit of this stress will be ascertained in each individual case, being controlled by the size and shape of each tank. By using only the movable sector form 20, as described, it is obvious that the large cost, as well as the labor, of building an entire form, as in present practice, is eliminated, thereby further reducing the cost of the tank. Although a circular tank has been shown and described, a tank of any desired size or shape may be constructed by this method.

The description which has been given recites more or less detail of a particular embodiment of the invention, which is set forth as new and use ful; however, I desire it understood that the invention is not limited to such exact details of construction, because it is manifest that changes and modifications may be made within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent, is:

1. The method of forming composite tanks which consists, in forming a plastic foundation, mounting a metallic reinforcing frame on said foundation, covering said frame with plastic material to form a tank wall, then filling said tank to stress said frame, and then coating said wall with plastic material to seal cracks and complete said wall.

2. The method of forming composite tanks which consists, in forming a plastic foundation, mounting a metallic reinforcing frame on said foundation, constructing a floor of plastic material within the foundation, covering said reinforcing frame with plastic material to form a tank wall, then filling said tank to stress said frame, and then coating said wall with plastic material to seal cracks and complete said wall.

3. The method of forming composite tanks which consists, in forming a plastic foundation, mounting a metallic reinforcing frame on said foundation, constructing a floor of plastic material within the foundation, covering said reinforcing frame with plastic material to form a tank wall, forming an expansion joint between said wall and the floor, then filling said tank to stress said reinforcing frame, and then coating said wall with plastic material to seal cracks and complete the wall.

4. The method of forming composite tanks which consists, in forming a plastic foundation, mounting a metallic reinforcing frame on said foundation, constructing a floor of plastic material within the foundation, covering said reinforcing frame with plastic material to form a tank wall, forming an expansion joint between said wall and the floor, then filling said tank to stress said reinforcing frame, then coating the outer surface of the tank wall with plastic material while the tank is still loaded, and finally emptying the tank and coating the inner surface of the Wall with plastic material to further seal cracks and complete said wall.

5. The method of forming composite tanks which consists, in forming a plastic foundation,

mounting a metallic reinforcing frame on said foundation, covering said frame with plastic material to form a tank wall, then filling said tank to stress said frame, then coating the outer surface of the wall with plastic material while the tank is still loaded to seal cracks, and finally emptying the tank and coating the inner surface of the wall with plastic material to further seal cracks and complete said wall.

6. The method of forming composite tanks which consists, in forming a plastic foundation, mounting a metallic reinforcing frame on said foundation, constructing a floor of plastic material within the foundation, covering said reinforcing frame with plastic material to form a tank wall, then filling said tank to stress said frame, then coating the outer surface of the wall with plastic material while the tank is still loaded to seal cracks, and after this coating is set emptying the tank and coating the inner surface of the tank Wall with plastic material to further seal cracks and complete said wall.

'7. The method of forming composite tanks which consists, in forming a plastic foundation, erecting a metallic reinforcing frame on said foundation, covering a section of the frame with plastic material to form a section of a tank wall, then covering the remainder of the frame section by section with plastic material to complete the tank wall, then filling said tank to stress said frame, and then coating said wall with plastic material to seal cracks and complete the wall.

8. The method of forming composite tanks which consists, in forming a plastic foundation, erecting a metallic reinforcing frame on said foundation, covering a section of the frame with plastic material to form a section of a tank wall, then covering the remainder of the frame section by section with plastic material to complete the tank wall, then filling said tank to stress said frame, then coating the outer surface of the wall with plastic material while the tank is still loaded to seal cracks, and then after this coating is set emptying the tank and coating the inner surface of the wall with plastic material to further seal cracks and complete said wall.

9. The method of forming composite tanks which consists, in forming a plastic foundation, erecting a metallic reinforcing frame on said foundation, forming a floor within the foundation, covering a section of the frame with plastic material to form a section of a tank wall, covering the remainder of the frame section by section with plastic material to complete the wall, forming an expansion joint between the wall and the floor, then filling said tank to stress said frame, and then coating said wall with plastic material to seal cracks and complete said wall.

10. The method of forming composite tanks which consists, in forming a plastic foundation, erecting a metallic reinforcing frame on said foundation, forming a fioor within the foundation, covering a section of the frame with plastic material to form a section of a tank wall, covering the remainder of the frame section by section with plastic material to complete the wall, forming an expansion joint between the wall and the floor, then filling said tank to stress said frame, then coating the outer surface of the wall with plastic material while the tank is still loaded and the reinforcing frame is under stress, and finally removing the load and coating the inner surface of the tank wall with plastic material to seal cracks and complete the wall.

FRANK W. CHAPPELL. 

